Abstract: :
Purpose: Fundus autofluorescence (FAF) imaging provides indirectinformation on the level of metabolic activity of the retinalpigment epithelium (RPE) by imaging lipofuscin accumulationin the RPE largely determined by the rate of turnover of photoreceptorouter segments. In typical retinitis pigmentosa (RP) with abnormalfundus findings, reduced FAF is seen in areas of photoreceptorcell loss. A subset of patients with Leber congenital amaurosis(LCA), however, have near normal fundi. It is uncertain whetherthe photoreceptor/RPE–complex is still viable in suchpatients.Methods: Three adult patients with LCA (LCA1, 24 yrs; LCA2,15 yrs and LCA3, 37 yrs) and one patient with typical RP (28yrs) as a control were studied. LCA3 was the mother of LCA2.The diagnosis was based on history, visual function and Ganzfeldelectroretinography according to the ISCEV standard. FAF wasrecorded with a cSLO (Heidelberg Retina Angiograph, HRA; HeidelbergEngineering, Heidelberg, Germany).Results: All LCA patients had vision reduced to perception oflight and had undetectable ERGs. The fundus was near normalin LCA1 and LCA2. LCA3 showed irregular pigmentation at thelevel of the RPE. FAF was virtually normal in LCA1, near normalin LCA2, and moderately abnormal in LCA3. The RP patient showedpreserved visual acuity, detectable but markedly abnormal ERGs,and profoundly abnormal FAF.Conclusions: The FAF findings in the LCA patients suggest thatthere is continuous metabolic demand from the photoreceptorsand thus that these photoreceptors are anatomically intact withretinoid turnover, but have lost function. These findings mayhave implications for future treatment. It is remarkable thatmore than 20 years of severe visual impairment associated withLCA can be associated with normal FAF indicating that retinalfunction may be amenable to rescue.